Fuel feeding control device for furnaces



1:" G. A. KOHOUT FEEDING CONTROL DEVICE FOR FURNACES FUEL 7 Sheet s-Sheet 1 Filed Sept. 25, 1933 March 15, 1938. A, K H UT 2,110,977

7 FUEL FEEDING CONTROL DEVICE FOR FURNACES Filed Sept. 25, 1933 7 Sheets-Sheet 2 I geocgc Q. flZ/zaa March 15, 1938. G, A. KOHOUT FUEL FEEDING CONTROL DEVICE FOR FURNACES 7 Sheets-Sheet 3 Filed Sept. 25, 1933 [hue/d al Gearye QUZIZ/ZOCLZ March 15, 1938.

G. KOHOUT FUEL FEEDING CONTROL DEVICE FOR FURNACES Filed Sept. 25, 1953 7 Sheets-Sheet 4 March 15, 1938. G A KQHQUT 2,110,977

\ FUEL FEEDING CONTROLDEVICE FOR FURNACES Filed Sept. 25, 1933 '7 Sheets-Sheet 5 v fizz/621507 6607" (3 Q. flZ/zoui March 15, 1938. a G A, KOHQUT I 2,110,977

FUEL FEEDING CONTROL DEVICE FOR FURNACES Filed Sept. 25, 1953 7 Sheets-Sheet 6 March 15, 1938. a. A. KOHOUT FUEL FEEDING CONTROL DEVICE FOR FURNACES Filed Sept. 25, 1933 7 Sheets-Sheet 7 Patented Mar. 15, 1938 UNITED STAT PATENT OFFEQE FUEL FEEDING CONTROL DEVICE FOR FURNACES 7 Claims.

My invention relates to furnaces and more particularly to a control system for providing flexible supervisory control of automatically operated furnaces,

In furnaces which the feeding of fuel is automatically stopped or started in response to changes in boiler pressure, furnace temperature, lapse of time or other control factors, the problems of controlling the rate of feeding while the feeding mechanism is in operation and the time sequence of operating the different units of a multiple unit feeding mechanism present certain difficulties.

It is a purpose of this invention to provide a control system which may be used in conjunction with automatic furnace controls to adequately regulate the rate of fuel feeding during the period of operation of the fuel feeding mechanism.

It is also a purpose of my invention to provide in a multiple unit fuel feeding system a novel control means for maintaining a definite time sequence of operation of said units which also makes possible independent operation of any unit at any time.

My invention contemplates also the provision of a novel control mechanism for controlling the length of time interval separating the a-ctuations of the fuel feeding units.

Other and more specific objects of the invention will appear as the description proceeds in connection with the accompanying drawings. It is to be understood, however, that the drawings and description are illustrative only and are not to be taken as limiting the invention except in so far as it is limited by the claims.

In the drawings- Fig. l is a side view partly in section illustrating a furnace of the stoker grate type to which my invention is applied;

Fig. 2 is a sectional view substantially on the line 22 of Fig. 1 showing the multiple fuel feeding units or stoker grates;

Fig. 3 is a vertical section through a part of the control mechanism employed;

Fig. 4 is a section on the line 44 of Fig. 3;

5 is a section on the line 5-5 of Fig. 3;

Fig. 6 is a section on the line 5-5 of Fig. 3;

Fig. '7 a top plan View of a portion of the top of the control box shown in Fig, 3 illustrating the control lever for setting the mechanism in the box of Fig. 3;

Fig. 8 is a front view with the cover removed of one of the solenoid units for connecting the drive shaft to the various fuel feeding units;

Fig. 9 is a section on the line 99 of Fig. 8;

Fig. 10 is a front View of a portion of the drive shaft and the mechanism for conecting it to the grate actuating mechanism;

Fig. 11 is a section on the line li|l of Fig. 10; and

Fig. 12 is a diagrammatic View illustrating the electrical connections to the various control elements for operating the fuel feeding units.

In illustrating my invention, I have applied it to a furnace where the fuel is fed down over the grates from the inlet by means of a series of stoker grate units in which the grate bars are rocked upon their pivots to move the fuel away from the entrance. In fuel feeding devices of this character, it is common to employ the control mechanism for stopping and starting the fuel feeding motor in response to changes in boiler pressure, and I have shown diagrammatically in Fig. 12 the wiring connections necessary for this purpose. I have also shown suitable connections to a timing switch operating in connection with the pressure switch for stopping and starting the fuel feeding motor at intervals when the pressure switch is open. In utilizing stoker grates of the rocking grate type, it is also essential that when the fuel feeding mechanism is stopped, the grates be left in level position, and this is accomplished by utilizing a limit switch which maintains the motor circuit closed after the pressure switch or the time switch has opened until the grates reach a level position. Such a structure is shown in my prior Patent No. 1,897,579.

My invention is directed to a device operating in conjunction with or independently of the control mechanism above referred to to connect and disconnect the drive shaft to the several feeding units.

In order that the general operation of the control mechanism may be properly understood, I will first describe the control circuits shown in Fig. 12.

Referring now to Fig. 12, the letters A, B, and C indicate the current supply lines from a threephase source for operating the mechanism. These lines are brought in to a terminal board it and connected to the line terminals LI, L2, and L3. This board carries a relay H which is adapted when energized to close the contacts at i2, i3, and id for energizing the motor. When contact if is closed, line A is connected through terminal Ll, contact if, winding of safety coil to the motor it. When contact i3 is closed, line B is connected through terminal L2 and contacts 53 to motor it; and, when contact id is closed, line C is connected through terminal L3, 55

contacts l4, and winding of the safety coil H to the motor. Since contacts |2, l3, and M are all closed by energization of relay II, it is evident that when this relay is energized the motor will be started; and, if for any reason the relay is deenergized, the motor will be stopped.

The safety devices l5 and I1 normally connect the terminals at |8 and IS in the line which leads to the relay I!. These safety devices l5 and I1 are merely overload relays which open their contacts when an excessive amount of current is being drawn by the motor |6.

The terminal L| is connected through the contacts l8 to the relay II, and the other side of the relay is connected through the contacts I!) to terminal Cl which is directly connected to terminal C2. The hand switch 20, which is a three-position switch is connected directly to terminal L3. It is evident that, if hand switch is moved to connect with its upper contact, an energizing circuit for relay H is immediately closed from, line A through terminal Ll, contacts l8, winding of relay contacts l9, terminals Cl and C2, upper contact of switch 20, terminal L3 to line C. This would, of course, close contacts l2, l3, and I4 and energize the motor so that the operator may, at any time he desires by moving the hand switch 20 to its upper position energize the motor |6.

Now if the hand switch 20 is moved to its lower contact, line C is connected through terminal L3, hand switch 20 to contact C3. The contacts of pressure switch 2|. time switch 22 and limit switch 23 are connected in parallel across contacts C2 and C3. Lines 24 and 25 lead from C3 and C2 respectively to the terminals of the pressure switch 2|. Lines 21 and 28 connect the opposite terminals of time switch 22 to terminals C3 and C2, respectively. The time switch is also shown with the usual energizing coil 29 which is connected on one side by the line 30 to terminal LI and on the other side through the line 21, switch 2|], to terminal L3 when the switch 20 is in lower position so as to maintain the clock mechanism of time switch 29 properly energized.

The limit switch 23 is connnected to terminal C3 by line 3| and to terminal C| by line 32, Cl being directly connected to terminal C2. This places the limit switch in parallel with the pressure switch and the time switch across the terminals C2 and C3.

Now if the hand switch 20 is in lowermost position, this connects line C through terminal L3 and switch 20 to terminal C3. Line A is already connected to terminal C2 through terminal L|, contacts I8, relay contacts I9, and terminal Cl. Therefore, if either switch 2|, 22, or 23 is closed, a circuit for energizing the relay II will be completed when the switch 20 is in its lowermost position. It is evident, therefore, that the motor may be started by the closing of the pressure switch 2| assuming that the hand switch 20 is in its lower position, and, if pressure switch 2| is maintained open, the periodical closing of switch 22 will also energize relay The limit switch 23, as will be brought out later, is only open when the stoker grates are in level position. The grates are, therefore, stopped in level position, and limit switch 23 cannot start the motor l6 from this position. However, if the motor is operating and both switches 2| and 22 are open, the limit switch 23 will maintain the motor energized until it moves the grates to level position and breaks the circuit at limit switch 23 to deenergize relay The controls just described are not in themselves the novelty of the present application, and I will now describe the operation of the circuit which controls the actuation of the stoker grates after the motor l6 has been energized.

As shown in Fig. 12, line A is connected through terminal Ll, contacts l2 and winding of safety device |5 to line 33. Line 33 leads to terminal SI of the supervisory control device 34. Line 32 connects to terminal S3 on the panel of the control device 34, and this terminal in turn is connected by line 35 to one side of each of the solenoids 36, 31, and 38. For the purpose of clarity, I will describe the circuit controlling the solenoids 36, 31, and 38 with the assumption that the hand switch 20 is on its upper contact to energize the motor l6. This places line C in direct connection with terminal Cl and C2. 33 indicates a rotary cam switch which is directly connected by line to terminal SI and line 33 which is in turn connected to line A when the motor is energized. The cam switch 39 has three contacts 4|, 42, and 43 which connect through the hand switches 44, 45, and 46, respectively, to terminals S4, S5, and S6, which are in turn connected by lines 41, 48, and 49 to the solenoids 36, 31, and 38, respectively.

Thus, if the contact 40 of the cam switch 39 engages contact 4 I, then switch 44, which is normally closed, will direct current from line A through terminal LI, contact I2 of relay I, winding of safety device I5, line 33, terminal SI, line 40, contacts 40', and 4|, switch 44, terminal S4, line 41 to solenoid 36; and then over a return circuit through line 35, terminal S3, line 32 to terminal C I, then to terminal C2 and through switch 20 and terminal L3 to line C. Solenoid 36 will thus be energized.

Over similar paths solenoid 31 will be energized when contact 40 engages contact 42 and switch 45 is closed, and solenoid 38 will be energized when contact 46 engages contact 43 and switch 46 is closed.

I have also shown push button switches 50, 5|, and 52 connected directly on one side to line 40 and on the other side to terminals S4, S5, and S6 so that by manually closing switch for example when the motor I6 is running the solenoid 36 may be operated even though contact 40' is not in engagement with contact 4|.

The circuit over which solenoid 36 is energized by closure of switch 50 leads from line A through terminal Ll, contacts |2 of relay winding of safety device l5, line 33, terminal SI, line 40, branch line 53, closed contact of switch 50 to terminal S4, line 41, winding of solenoid 36, and back over lines 35 and 32 through terminals C|, C2, and switch 20 to terminal L3 and line C.

Now if the automatic control devices such as pressure switch 2| and time switch 22 are in circuit, there is really no difference in the operation of the devices 36, 31, and 38 as in this case, so long as either pressure switch 2|, time switch 22, or limit switch 23 happen to be closed and 20 is in its lower position, the energizing circuit for element 36 will extend from line A over the path previously described to line 33, then through the control 34 to terminal S4 and line 41 and back over line 35 and 32 to terminal Cl and from terminal CI to terminal C2. The circuit is completed from terminal C2 in case pressure switch 2| is closed over line 25, contacts of pressure switch 2|, line 24, terminal C3 to switch 2|] at its lower. contact which connects up line C to complete the energizing circuit for 36. Similarly, if the time switch 22 is closed, the energizing cir- 'cuit for 36 will be closed through the lines 2'! and 28 and the closed contacts of time switch 22.

When the limit switch 23 is closed and the other two switches are open, the energizing circuit for 36 may be traced over the following path: From line A, through terminal Ll, contacts l2 of relay I I, winding of safety device l5, line 33 to terminal SI of control device 34, then through the control device 34 to terminal S4, line ll to 36, back over line 35 to terminal S3, then through closed contact of limit switch 23 to terminal S2 and over line 3! to terminal C3 and then to switch 28 at its lower contact back to terminal L3 and line C.

The manner in which the solenoid devices 35, 31, and 38 may be periodically energized by the cam switch device 39 at any time the motor is is running will, it is believed, be clear from the above description. Also, it is believed to be evident that any time the motor I6 is running, either of the devices 35, 31, or 38 may be energized by pressing the corresponding push button 50, or 52.

I will now describe the mechanism which is caused to be operated by the energization of the elements 36, 31, and 38.

I have shown my invention as applied to a fuel feeding device utilizing stoker grates of the rocking type. These grates are indicated by the numeral 53' (see Fig. 2) and there are three sec tions or units such as 54, 55, and 56 all of which are operated from a common drive shaft 51 which in turn is driven from motor In by means of a disc and crank pin 58, link 59. and arm 60. Suitable bearings 51a, 51b, and 51.0 are provided for the shaft 51. In addition, a link 6! connects a second arm 6| fixed on the shaft 51 to a similar arm 52 mounted on the shaft 63 which drives the cam switch 39. The connections between the shaft 5! and the three fuel feeding units 54, 55, and 56 are the same for each unit. These connections are shown most clearly by Figures 1, 10, and 11. The rocking grate bars are connected by depending arms such as 64 to the actuating link 65 which in turn is secured to the arm 65 which is pivotally mounted upon the shaft 51. A

suitable sleeve bearing 5! serves to take the wear of the arm 66 off the shaft 51. This sleeve bearing is secured to the member 68 which is in turn carried by the shaft 5! and secured thereto by suitable pin 69 so as to rock with the shaft.

The member 66, it will be noted, is forked at m to provide two arms which fit on opposite sides of the member 68. and a shear p n H carries a roller 12 between the two arms. The member 68 has the shoulder 13 thereon which is adapted to engage the roller when the member 68 and shaft 5'! are rocked in a counterclockwise direction so as to force the roller 12 and with it the arm 65 to move with the shaft in this direction. Opposite the shoulder 13 the member 68 has pivoted thereto .a pawl M which in its normal inoperative position swings down by its own weight into the position shown in full lines in Fig. 11. The position shown in Fig. 11 is that of resting position for the fuel feeding grates, and it is believed to be evident that, if the shaft 51 and member 58 are rocked in a clockwise direction from this position, the roller 12 will ride between the member 58 and the pawl It.

Now, if the pawl M is raised up into the dotted line position shown in Fig. 11, the same rotation will cause the end of this pawl to engage the roller i2 and thus move the arm $6 with the shaft 51 thus rocking the grates 53 to cause a fuel feeding operation. It should be understood, of course, that each of the fuel feeding units 54, 55, and 56 is connected to shaft El by mechanism like that shown in Figs. and 11.

The pawl W- has the heavy spring extension '55 projecting toward the furnace, and this extension is adapted to be engaged by the depending arm To depending from the solenoid device When the solenoid device 35 is energized, it rocks the arm if; from the full line position shown in Fig. 11 to the dotted line position shown in this figure. The extension '55 then, when the shaft 51 is returning a counter-clockwise direction to the position shown in Fig. 11, will be caught by the end of the arm it to move the pawl "a l up into the dotted line position shown in Fig. 11, and thus cause the pawl to engage the roller l2. It will be noted that the end face if of pawl is is so shaped that once it is pressed against the roller '52 and held there by the force necessary to turn the arm it cannot fall out until the pressure is released or until the clockwise stroke of the shaft 51 is completed. The energizing of the solenoid devices such as 35 is so timed with respect to the rocking of shaft 5? that the arm. i6 is swung into its dotted line position while the spring member '55 is out of the way. This timing operation will be brought out more clearly after the mechanism has been fully described. Of course. if the arm '56 is caused by hand operation of push button switches such as as to to move toward the member it when the member i5 is in the full line position shown in Fig. ll, nothing will happen until the shaft 5? has swung far enough to bring 75 below the end of the arm is.

From the above description, it is believed to be evident that when the solenoid device 3% is energized to swing arm "68 out into the path. of the spring '55, the pawl will serve to connect the arm to the shaft Ell for rotation with the shaft in a clockwise direction; and naturally the rotation in the opposite direction will. through the medium of the roller l2 and the shoulder 18. bring the arm 65 back to the position shown in Fig. 11 on the return stroke.

The manner in which solenoid device moves the arm ill will now be described.

Referring to Figs. 8 and 9, the solenoid device 36 is housed in a casing '18 which is suitably mounted on a furnace as shown in Fig. and further to protect the solenoid device from the dust and dirt around a furnace, a cover or housing 19 hooks into the notch at 8%) (see Fig. 11) at the top of the casing l8 between the mounting lug of the casing and the furnace wall. This housing projects out over the device 68 mounted on the shaft 5? and thus keeps the falling material such as particles of coal and the like from disturbing the operating mechanism. The lower end of the casing 3 has the recess 36 cast therein, and the arm l8 extends up into this recess where it is mounted upon shaft that projects through the walls of the recess 3 i, and is provided at its opposite ends with the arms 82' and These arms are connected by the coil springs and 35 to the pin 85 which passes through the lower end of the solenoid plunger 5?. The coil 38 is energized over the wires 35 and M connected to the terminals such as 89 and 9d. The numeral Qt indicates the laminated frame of the solenoid, and the numeral 92 indicates an extension from. the upper end of the plunger 87 which carries a stop piece 93 of non-magnetic material to engage the spring 94 when the solenoid plunger is raised upon energizing of the coil 88. The purpose of the spring 94 is, of course, to insure release of the plunger and its downward movement when the energizing circuit of the solenoid is broken as otherwise the residual magnetism of the laminations 9| and the plunger 81 might hold the plunger in raised position. It is believed to be evident from an inspection of Figs. 8 and 9 that, when plunger 87 is raised, the arms 82 and 83 will swing the arm I6 into the dotted line position illustrated in Figs. 9 and 11 for engagement with the spring I5.

The manner in which the solenoid is energized has already been described in connection with Fig. 12.

I will now describe the mechanism of the control device 34.

Referring now to Figs. 3 to '7 inclusive, I have already described how the drive shaft 51 is connected through arm SI, link BI and crank arm 62 to the driving shaft 63 for the control device 34. The drive shaft 63 has a depending arm 95 (see Fig. 4) which engages an adjusting screw 96 on the frame 91 that carries the limit switch 23. The limit switch 23, as shown, is a mercury switch in which the two contacts such as 98 and 99 are normally separated when the arm 95 is in the position shown in Fig. 4. This position of arm 95 corresponds to the raised position of the arm 02 which corresponds to the level grate position of arm 66 as shown by Figs. 1 and 11. In other words, the limit switch 23 is open when the grates are level. However, when the arm 95 is moved to the right from the position shown in Fig. 4 in response to a downward pull on arm 62, the weight of the frame 91 levels off the mercury switch 23 since the frame 91 can turn about its pivot at I00.

The shaft 63 has an arm IOI which is linked by means of link I02 to the arm I03 of the clutch device I04. Link I02 is slotted as indicated at I02 so that, while there is a downward movement of arm I03 in response to down movement of arm IOI to the limiting position shown in Fig. 4, the upward movement of arm IOI does not move arm I03 upwardthe pin on arm IOI merely riding in the slot of link I02. A spring I05 is connected at its one end to the housing I06 of the control device 34 and is connected under tension at its other end to arm I03 so that it tends to draw arm I03 upwardly at all times.

Clutch device I04 is mounted on shaft II, but is free to rotate thereon. This clutch device has mounted thereon a pin I08 which engages with a cam I09 for adjusting the amount of rotation which will be transmitted to clutch device I04 for each movement of shaft 63 and arm IOI. Within the flange III! of clutch device I04, there are mounted a series of arms such as III, H2, and H3 which are urged by means of the springs II4 outwardly against the flange IIO, these arms being pivoted to a central member II that is secured to shaft I01 by pin II6. It will be noted that the arms such as I II are slightly offset from radial position so that rotation of member I04 in a clockwise direction causes these clutch arms to engage or press against the flange H0 and thus rotate the central member II5 with the clutch member I04.

The shaping of the arms such as III, H2, and H3 in order to obtain the proper clutching effect is one that involves considerable difiiculty,

and I have discovered that by making these arms in a certain fashion I can obtain a very effective one-way clutch action. The outer face of the arm such as III is curved on the same radius as the inner flange IIO so that the entire face may engage the flange. One edge of this end face of the arm is shorter than the other and the length of the arm must be such as to permit the short edge to approach as closely as possible to the intersection of a radial line through the pivotal axis of the rim I I0 and the pivotal axis of the arm with the rim. In the figure I show the short edge as not quite reaching such intersection as allowance must be made for inaccuracies. This permits the full end face of the arm to engage the rim. If the arm is too short then it sticks and wont release, if too long it wont grip and slides on the rim. Since the bearing between the rim and end of the arm is quite large it is slow to wear and gives a long useful life. It appears necessary however to follow dimensions closely. For example, with the flange IIO made on a radius of one and one-fourth inches and the pivot of the arm III spaced one-half inch outwardly from the center of the shaft I 01, the arm having a one-fourth inch face to engage the flange IIO, the distance from the pivot center of the arm to the nearest end of the face of the arm that engages the flange H0 should be approximately one-sixteenth of an inch shorter than the distance from the pivot center to the other end of the face. With these proportions, I find that the clutch operates very smoothly in transmitting the rotary motion of the member I04 to the member I I5 in one direction and releases easily to permit reverse rotation of the member I84 without turning the member II5.

It is believed to be evident from an inspection of Fig. 4 that, when arm 62 is pulled down by the link 6|, the spring I05 will be allowed to pull the arm I03 upwardly and to turn the member I04 in a counterclockwise direction. The pin I08 limits the amount of this motion, however, by striking against the cam surface on the plate I09. Then on the reverse stroke when the arm 62 is moved upwardly the arm IOI will move the disk I04 back down to limiting position, but the amount of movement of I04 will, of course, be only the amount which it was allowed to move in a counterclockwise direction by the pin I08 and cam I09. In this clockwise rotation of I04, the clutch arms cause the member II5 to rotate with I04. By turning the cam plate I09, by means of the finger piece III, the amount of rotation of the member II5 for each rocking motion of the shaft 63 can be varied over a wide range. In this way, angular movement of shaft I0! step by step in one direction is accomplished. On the top of the casing I00 there is an indicating plate IIO which may be suitably marked as indicated in Fig. '7 for indicating the setting of the finger piece I I1.

Referring now'more particularly to Fig. 3, it will be noted that there is a second clutch disk I20 opposite the member I54 which is engaged by arms I2I. The arms IZI are exact duplicates of arms such as III, H2, and I I3 and make the same angle with the radius through their pivots from the shaft I0'I as arms III, IIZ, and H3 do. Disk I20 is stationary, being keyed in the housing I05 as indicated at I22. The clutch arms I2! and disk I20, therefore, act to prevent rotation of H5 in a counterclockwise direction although permitting it to rotate freely in response to the force transmitted upon clutch device I04 through the arms Ill, H2, and H3.

The motion of the shaft I0? is transmitted through the bushing I23 of insulating material which is pinned to the shaft ml to a contact carrying disk i2 l also of insulating material. This disk has the cut out notch at I25 (see Fig. 5) and the shoulder at I26 over which the contact member i2? is bent. The contact member 527 is integral with the sleeve 52'! which is fixed on the bushing i223. The disk i28, also of in sulating material, is rotatably mounted on shaft till and carries a series of spring pressed contacts iES, ltd, and 535 which correspond to contacts ii, 42, and 43 shown in Fig. 12, the contact i2! corresponding to contact 49' of Fig. 12. Suitable terminals such as I32 and I33 are provided in conjunction with the contacts I29, H0, and EM for connection to the wire leads shown in Fig. 12 as leading from contacts 3!, 42 and #3. Disk 528 carries also an arm Hit in contact with the sleeve i2'i which is also provided with a suitable terminal for connection to the wire 48 of Fig. 12. Disk 523 has an arm I35 which is connected by link i371 to the arm 38 which is pinned to the shaft 63 so as to rock therewith. The disk i2 1 is moved by the shaft 5 ii? step by step in a clockwise direction at a rate depending upon the setting of the cam E69, and, as it moves, the various contacts such as IE9, H36, and IS! drop down onto the contact I27 to make circuit through the cam switching device from line 49 through terminal i335, arm I3 1, contact tilt, and contact i29, I35, or lii to the terminal ii, 42, or 43. The action of disks E25 and E28 will be best understood from Figures 3 and 5. Disk 92% rocks to and fro as shaft 63 rocks, and shaft 63 rocks in time with the rocking of shaft 5?. Disk I24, however, is moved along by shaft It! step by step in the direction indicated by the arrow in Fig. 5.

The timing relation between shaft 55'? and disk E28 will appear from Figs. 1, 4, and 5. When shaft 57 is moved clockwise, shaft $3 is moved counterclockwise in Figs. 1, 4, and 5, and disk I 28 is, therefore, also moved counterclockwise.

The disk I 24 is moved clockwise step by step during the clockwise movement of disk 528. On the counterclockwise movement of !28, or while shaft 51 is moving clockwise as shown in Figs. 1 and 11 to move spring i5 away from bar iii, the contact disk I24 is stationary. It is during this movement that the contacts I29, etc. drop down on I2? to energize the solenoids such as 36 thus swinging bar I6 at a time when the spring 715 is out of the way. During the next clockwise movement of disk i228, its contact such as E29 engages shoulder I21" and moves cam disk I25 along with it for the full stroke of H23.

he next or return stroke causes the contact such as I29 to drop off shoulder I26 into notch I25 to thus prevent that contact from engaging i2? again on the return stroke.

The maximum angular movement of disk E24 by drum Ifi l for one step is somewhat less than the angular rocking movement of disk E28, and the contact element I2? is made of substantial width in comparison with the distance disk 528 moves in order to insure contact on the advance movement of the contacts. For example, contact I 21 is about equal in width to the distance it would move for an an angular movement of 30 degrees of disk 12%. The maximum angular movement of disk I25 by drum N34 is about 30 degrees, and the angular movement of disk I28 is about 40 degrees.

50, 5|, and 52 are ordinary commercial push button switches which are adapted to close circuit through them when the push buttons such as I40 are pressed. The switches 44, i5, and 45, only one of which is shown in Fig. 4 and which are hidden by the switches 50, iii, and 52 in Fig. 6, are also a'standard commercial switch which are adapted to open and close their contacts in response to movement of the levers such as I M. Switch M and switch 50 are connected in the manner shown in Fig. 12, and this is also true of switches 45 and 5|, and 4E and 52. The wiring is left off in the mechanical figures for the sake of clearness. The terminal strip M2 isthe one on which the contacts SI, S2, etc. are mounted.

In order to make the operation of this device more clearly understood, I will assume that the time switch 22 is closed and the motor I6 is operating in accordance with the description given of the circuit in connection with Fig. 12. With the motor running, the crank 58, through the medium of the link 59 and arm 60, rocks the shaft 5?; and also the rocking of shaft 5'! through the arm 6 I link GI and arm 62 transmits a rocking motion to shaft 63. Rocking of shaft 63 causes arm MI to move up and down. As arm lill moves up, the spring m5 pulls arm 503 upwardly to rotate drum EM in a counterclockwise direction until the pin I08 strikes the cam surface of cam plate I09. Further movement of the arm lilll merely causes this pin to move up in the slot I92 of link Hi2.

Now when the rocking motion is reversed and arm idl is moved downwardly in response to a downward movement of arm 62 by link 61 and arm St, the first part of the movement merely moves the pin on arm Hill to the bottom of slot 482'. When this point is reached, link I02 is pulled down which causes arm M3 to rotate the drum H34 in a clockwise direction as shown in Fig. 4. The clutch arms III, H2, and H3 then grip the flange IN and cause the member II5 to rotate in a clockwise direction thus rotating shaft ID! in the same direction, and shaft I01 carries with it the disk I24 and contact I2? mounted thereon. While this action is taking place, disk H8 is also being rocked in a clockwise direction by arm I36, link I3l, and arm I38 which is mounted on shaft 53. This action will be continued until one of the contacts, say I31, drops down onto contact I21 during the counterclockwise rocking movement of. I28 at which time a circuit will be completed from wire 48 through contact 48' which corresponds to arm I34 to contact E21 and then to contact I3I which corresponds to contact 33 to thus supply the current from line A over lines 33 and 46 up to the switch 66.

Assuming that switch d6 is closed, this connects line 49 in circuit so as to supply current to the solenoid device 38. Solenoid device 38 then attracts its armature or core 31 pulling it upward and causing the stop on 93 at the top thereof to strike spring 94 and at the same time the springs 34 and 85 are caused to rotate the shaft 82 to swing the connecting arm I6 from the full line position shown in Figs. 9 and 11 to its dotted line position. This positions the arm I6 to engage on top of the spring l5 on the return stroke of shaft 5'5 so as to move the pawl I4 up into dotted line position as shown in Fig. 11. Then as the shaft 5? is rocked in a clockwise direction as shown in Fig. 11, the pawl '54 engages roller 12 to move the arm 66 with the shaft, thus pulling the link 65 to the left to rock the grates upwardly and to feed the fuel forward on unit controlled by the solenoid device 38.

When the shaft 51 starts back in the opposite direction, that is when arm 60 is being pulled upwardly, arm 62 is also being moved upwardly, but prior to this on the clockwise stroke of shaft 51, arm 62 was pulled down which turned shaft 63 in a counterclockwise direction sufficiently to break the contact between l3l and I2! by pulling the tip of l3l oif into the cut-out portion I25 of disk I24. This released solenoid device 38 and allowed its arm 16 to fall back into vertical position. The pawl 14, however, could not become disengaged owing to the shape of its end 11.

Going back now to the return or grate leveling stroke of the shaft 51, the upward movement of arm 80 and arm 62 by the motor causes the shoulder 13 on member 68 to engage roller 12 and the member 14 to drop down in idle position. The return stroke of the shaft, therefore, through the medium of shoulder 13 and roller 12, pushes the arm 66 back into the position shown in Fig. 11 thus to level the grates. During this stroke, arms liil and I38 are pulled downward resulting in further advancing the member H5 through the medium of arm I03, disk I04, and clutch arms lli, H2, and H3, and this by rotating shaft in! steps the disk I24 one step farther around in a clockwise direction. The stepping action would then continue until another contact such as I30 dropped onto contact [2! when the solenoid device 31 is energized to rock the grates controlled by it in the same fashion just described. In this manner, the different fuel feeding units are operated automatically in timed relation one after the other so long as the motor remains energized.

If at any time while the motor is energized the operator feels that one of the feeding units should be given an extra operation, he merely presses the push button such as 50, 5|, or 52, mounted thereon, and this will energize a solenoid device 36, 3?, or 38 directly from line A over line 33, line 40, and line 53 through the contacts of the closed switch 50, 5|, or 52 and its associated line 41, 48, or 49. The actuation of the solenoid device will connect the shaft 51 to that particular feeding unit and operate it. The manual operation leaves the automatic operation undisturbed as to timing, and the automatic operation then continues in the fashion hereinbefore described.

From the above description, it is believed that the construction and operation of this device will be clear to those skilled in this art and the advantages thereof readily apparent.

Having thus described one specific form of my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a furnace operating system, a drive member, a rocking grate, a grate rocking mechanism, and connecting means for connecting the drive member to said mechanism, control means for controlling the connecting means comprising an actuating member movable into position to cause the connecting means to connect the drive member to said mechanism, electro-magnetic means for operatively moving said actuating member, a cam switch driven from said drive member for periodically energizing said electromagnetic means, and manually operable means to energize said electro-magnetic means between the energizations thereof by said cam switch.

2. In a furnace operating system, a drive member, a rocking grate, a grate rocking mechanism, and connecting means for connecting the drive member to said mechanism, control means for controlling the connecting means comprising an actuating member movable into position to cause the connecting means to connect the drive member to said mechanism, electro-magnetic means for operatively moving said actuating member, and a cam switch driven from said drive member for periodically energizing said electro-magnetic means.

3. In a control device for furnaces, a plurality of rocking grate units and a common drive member and individual connecting devices between each unit and said member normally maintaining the units disconnected from the drive member, electro-magnetic devices one for each unit each adapted when energized to cause the connecting device for that particular unit to couple the drive member to the unit, and control means for said electro-magnetic devices comprising a cam switch driven from said drive member and having contacts, and circuit connections connected with said contacts for energizing the electro-magnetic devices successively.

4. In a control device for furnaces, a plurality of rocking grate units and a common drive member and individual connecting devices between each unit and said member normally maintaining the units disconnected from the drive member, electro-magnetic devices one for each unit each adapted when energized to cause the connecting device for that particular unit to couple the drive member to the unit, and control means for said electro-magnetic devices comprising a cam switch driven from said drive memher and having contacts, and circuit connections connected with said contacts for successively energizing the electro-magnetic devices, and manually operable switches for energizing said electro-magnetic devices.

5. In a control device for furnaces, a plurality of rocking grate units and a common drive member and individual connecting devices between each unit and said member normally maintaining the units disconnected from the drive member, electro-magnetic devices one for each unit each adapted when energized to cause the connecting device for that particular unit to couple the drive member to the unit, and control means for said electro-magnetic devices comprising a cam switch driven from said drive member and having contacts, and circuit connections connected with said contacts for successively energizing the electro-magnetic devices, said electro-magnetic devices each consisting of a solenoid, a pivoted arm, and resilient means connecting the solenoid and said arm for moving the arm into operating position when the solenoid is energized.

6. In a control device for furnaces, a plurality of rocking grate units and a common drive memher and individual connecting devices between each unit and said member normally maintaining the units disconnected from the drive member, electro-magnetic devices one for each unit each adapted when energized to cause the connecting device for that particular unit to couple the drive member to the unit, and control means for said electro-magnetic devices comprising a cam switch driven from said drive member and having contacts, and circuit connections connected with said contacts for successively energizing the electro-magnetic devices, said control means having an adjusting device for varying the length of time between energizations of the electro-magnetic devices.

said electro-magnetic devices comprising a cam switch driven from said drive member and having contacts, and circuit connections connected with said contacts for successively energizing the electro-magnetic devices, and manually operable switches in parallel with the cam switch contacts for energizing said electro-magnetic devices.

GEORGE A. KOHOUT. 

